Tires

Nevegals will be fine. I had been running the 2.1 version until it wore out and liked it. Everyone has their tire preference as I'm sure they'll share, but if that's yours it will be fine.

As far as tubes/slime, I'm sure people are going to tell you it's absolutely necessary to use slime/tubeless but I can tell you Ive still yet to get a flat without using either. If you don't want to, don't. It might be good vacation riding insurance though. (not that it takes a huge amount of time to change a tube) You could always buy the pre slimed tubes if you were worried about it, they are only a few bucks extra.

Just bring some extra tubes and put them in your Camelback. I found if you stick to trails that are heavily ridden then most of the cacti needles have been picked up by everyone's tires

If you find your going through tubes then just stop by the lbs and buy some Slime or pre-slimed tubes.

(Our economy could use your extra $$$)